Protractor - Photo Angle, Tilt

A protractor that opens straight to the dial. Lay an object on the screen, place three points on a photo, or stand the phone on an edge to read a tilt.

■ Screen protractor

- A full 360° dial with marks every degree and bold marks every 15°.

- Drag either arm, or move the centre dot anywhere on the screen.

- Tap the number to type an angle, and the arm turns to it.

- Half degree buttons for small turns, and a lock so the arms stay put.

- The arm sticks to 15°, 30°, 45° and other multiples of 15° when it comes close. You can turn this off.

- Read clockwise or counterclockwise.

■ Angle on a photo

- Pick a photo from your gallery, take one with your camera app, or share a photo to the app.

- Place a corner point and two arm points. A magnifier shows what is under your finger.

- Pinch to zoom in for small details.

- Save or share the photo with the angle marked on it.

■ Tilt

- Lay the phone flat to see front–back and left–right tilt with a bubble.

- Stand it on an edge to read the angle of that edge.

- Set zero on a surface you trust, and hold a reading to look at it later.

- The number turns to stay upright when the phone is on its side.

■ How your photos are handled

- Only the photos you choose are read. They stay on your device and are not uploaded.

- The app does not ask for camera permission. Taking a photo opens your own camera app.

- A marked photo leaves the app only when you save or share it.

■ Good to know

- An angle on a photo is true only when the photo is taken straight on. A photo taken at a slant changes how angles look.

- Tilt readings depend on your phone's sensor. Setting zero on a flat surface helps.

- On the screen protractor your finger sets the limit, so use the half degree buttons or type the angle.